Tunable pH Sensitive Lipoplexes.

To provide long circulating nanoparticles able to carry a gene to tumor cells, we have designed anionic pegylated lipoplexes which are pH sensitive. The reduction of positive charges in nucleic acid carriers allows reducing the elimination rate, increasing circulation time in the blood, leading to improved tumor accumulation of lipid nanoparticles. Anionic pegylated lipoplexes have been prepared from the combined formulation of cationic lipoplexes and pegylated anionic liposomes.

Europium labeled lactosylated albumin as a model workflow for the development of biotherapeutics.

Lactosylated albumin is currently used as a radiopharmaceutical agent to image the liver asialoglycoprotein receptors and quantify hepatic liver function in various diseases. A lactosylated protein (LACTAL) conjugate showed excellent liver uptake compared to non-lactosylated protein and a high signal to noise ratio, based on the biodistribution in mice using Tc-scintigraphy. However, in the laboratory, it is useful to have a method that can be used in daily practice to quantify cellular targeting or biodistribution.

Lipids for Nucleic Acid Delivery: Cationic or Neutral Lipoplexes, Synthesis, and Particle Formation.

Lipidic vesicles have been extensively studied for their capacity to condensate and deliver nucleic acids to the cells. Many different amphiphilic lipidic structures have been proposed each of them bringing some advances in nonviral gene transfection. The ionic or neutral nature of the lipids induces tremendous differences in the behavior of the corresponding liposomes, from the complexation of nucleic acid to the delivery to the cell.

Assessment of the targeting specificity of a fluorescent albumin conceived as a preclinical agent of the liver function.

In the context of increasing liver diseases, no contrast agent is currently available in Europe and the United States to directly assess the liver function. Only neolactosylated human serum albumin is being clinically used in Asia. In order to perform preclinical studies in the context of liver diseases, we conceived a fluorescent lactosylated albumin for the quantification of liver functional cells (l-Cyal).

Novel Perfluorinated Triblock Amphiphilic Copolymers for Lipid-Shelled Microbubble Stabilization.

Amphiphilic triblock (Atri) copolymers made of perfluorinated alkyl chain linked to hydrocarbon chain and methoxy-poly(ethylene glycol) of three different molecular weights were synthesized. In vitro evaluation demonstrated that these new compounds were noncytotoxic. Characterization and interaction of each triblock copolymer with a branched polyamine myristoyl lipid (2-{3[bis-(3-amino-propyl)-amino]-propylamino}- N-ditetradecyl carbamoyl methyl-acetamide, DMAPAP) were studied by the Langmuir film method and thermal analysis.

Cyanine derivative as a suitable marker for thermosensitive in situ gelling delivery systems: In vitro and in vivo validation of a sustained buccal drug delivery.

Buccal administration route is a promising way for a large number of drugs exhibiting a low oral bioavailability. The present work describes the formulation and evaluation of a mucoadhesive and thermosensitive in situ gelling delivery system based on poloxamer 407, poloxamer 188 and xanthan gum for buccal drug delivery. First, the mucoadhesion properties were evaluated using a tensile test.

Cationic microbubbles and antibiotic-free miniplasmid for sustained ultrasound-mediated transgene expression in liver.

Despite the increasing number of clinical trials in gene therapy, no ideal methods still allow non-viral gene transfer in deep tissues such as the liver. We were interested in ultrasound (US)-mediated gene delivery to provide long term liver expression. For this purpose, new positively charged microbubbles were designed and complexed with pFAR4, a highly efficient small length miniplasmid DNA devoid of antibiotic resistance sequence.

Characterization of Positively Charged Lipid Shell Microbubbles with Tunable Resistive Pulse Sensing (TRPS) Method: A Technical Note.

Microbubbles are polydisperse microparticles. Their size distribution cannot be accurately measured from the current methods used, such as optical microscopy, electrical sensing or light scattering. Indeed, these techniques present some limitations when applied to microbubbles, which prompted us to investigate the use of an alternative technique: tunable resistive pulse sensing (TRPS).

Controlling aminosilane layer thickness to extend the plasma half-life of stealth persistent luminescence nanoparticles in vivo.

Therapeutics and diagnostics both initiated the development and rational design of nanoparticles intended for biomedical applications. Yet, the fate of these nanosystems in vivo is hardly manageable and generally results in their rapid uptake by the mononuclear phagocyte system, i.e.

Fine tuning of mixed ionic and hydrogen bond interactions for plasmid delivery using lipoplexes.

Non viral gene transfection has been mostly reached via cationic polymer and lipid, required for DNA complexation and cell internalisation. However, cationic charges often induce cytotoxicity and limit the efficacy of the lipoplexes in vivo due to their fast elimination from the blood stream. Few years ago, we had developed noncationic lipid interacting with DNA via hydrogen bond interactions.

Mesoporous persistent nanophosphors for in vivo optical bioimaging and drug-delivery.

Based upon the ambitious idea that one single particle could serve multiple purposes at the same time, the combination and simultaneous use of imaging and therapeutics has lately arisen as one of the most promising prospects among nanotechnologies directed toward biomedical applications. Intended for both therapeutics and diagnostics in vivo, highly complex nanostructures were specifically designed to simultaneously act as optical imaging probes and delivery vehicles. Yet, such multifunctional photonic nanoplatforms usually exploit fluorescence phenomena which require constant excitation light through biological tissues and thus significantly reduce the detection sensitivity due to the autofluorescence from living animals.

The in vivo activation of persistent nanophosphors for optical imaging of vascularization, tumours and grafted cells.

Optical imaging for biological applications requires more sensitive tools. Near-infrared persistent luminescence nanoparticles enable highly sensitive in vivo optical detection and complete avoidance of tissue autofluorescence. However, the actual generation of persistent luminescence nanoparticles necessitates ex vivo activation before systemic administration, which prevents long-term imaging in living animals.

Cationic lipid nanocarriers activate Toll-like receptor 2 and NLRP3 inflammasome pathways.

Unlabelled: We provide evidence that cationic lipids, usually considered as a safe alternative to viral vectors as nanocarriers for gene therapy or drug intracellular delivery, do not behave as inert material but do activate cellular signalling pathways implicated in inflammatory reactions. We show here that the cationic lipid RPR206252 induces NF-κB activation, and the production of TNF-α, IL-1β, IL-6 and IFN-γ by human or mouse macrophage cell lines. Further, we demonstrate that the activation of inflammatory cascades by RPR206252 is dependent on Toll-like receptor 2 (TLR2), the natural sensor of bacterial lipopeptides and NOD-like receptor protein 3 (NLRP3), the major inflammasome component.

Lipidic spherulites: formulation optimisation by paired optical and cryoelectron microscopy.

Objective of this study was to assess the various steps leading to spherulite obtention by means of optical and cryoelectron microscopy. The formulation, resting and hydration steps were optimised. Green-based process and organic-based process were compared.

Liposomal encapsulation of the natural flavonoid fisetin improves bioavailability and antitumor efficacy.

The natural flavonoid fisetin (3,3',4',7-tetrahydroxyflavone) has shown antiangiogenic and anticancer properties. Because of fisetin limited water solubility, we designed a liposomal formulation and evaluated its biological properties in vitro and in Lewis lung carcinoma (LLC) bearing mice. A liposomal formulation was developed with DOPC and DODA-PEG2000, possessing a diameter in the nanometer range (173.

Xyloglucan-derivatized films for the culture of adherent cells and their thermocontrolled detachment: a promising alternative to cells sensitive to protease treatment.

By taking advantage of a natural and abundant polymer as well as a straightforward film formation technique, this paper focuses on the conception and use of a new alternative tool for thermo-controlled cell detachment. Thermoresponsive xyloglucan was produced after partial galactose removal by a 24 h reaction with β-galactosidase. The obtained polymer (T24) was then activated by reaction with 4-nitrophenyl chloroformate (NPC) in order to graft a cyclic peptide presenting an arginine-glycine-aspartic acid (RGD) motif.

Lipids for nucleic acid delivery: synthesis and particle formation.

Lipidic vesicles have been extensively studied for their capacity to condensate and deliver nucleic acids to the cells. Many different amphiphilic lipidic structures have been proposed, each of them bringing some advances in nonviral gene transfection. The ionic or neutral nature of the lipids induces tremendous differences in the behavior of the corresponding liposomes, from the complexation of nucleic acid to the delivery to the cell.

Functionalized single-walled carbon nanotubes containing traces of iron as new negative MRI contrast agents for in vivo imaging.

Single-walled carbon nanotubes (SWCNTs) containing traces of iron oxide were functionalized by noncovalent lipid-PEG or covalent carboxylic acid function to supply new efficient MRI contrast agents for in vitro and in vivo applications. Longitudinal (r(1)) and transversal (r(2)) water proton relaxivities were measured at 300 MHz, showing a stronger T(2) feature as an MRI contrast agent (r(2)/r(1)  = 190 for CO(2) H functionalisation). The r(2) relaxivity was demonstrated to be correlated to the presence of iron oxide in the SWNT-carboxylic function COOH, in comparison to iron-free ones.

In vitro targeting of avidin-expressing glioma cells with biotinylated persistent luminescence nanoparticles.

Far red emitting persistent luminescence nanoparticles (PLNP) were synthesized and functionalized with biotin to study their targeting ability toward biotin-binding proteins. First, the interaction of biotin-decorated PLNP with streptavidin, immobilized on a plate, was shown to be highly dependent on the presence of a PEG spacer between the surface of the nanoparticles and the biotin ligand. Second, interaction between biotin-PEG-PLNP and free neutravidin in solution was confirmed by fluorescence microscopy.

Lipothioureas as Lipids for Gene Transfection: A Review.

Non-viral gene therapy requires innovative strategies to achieve higher transfection efficacy. A few years ago, our group proposed bioinspired lipids whoseinteraction with DNA was not based on ionic interactions, but on hydrogen bonds. We thusdeveloped lipids bearing a thiourea head which allowed an interaction with DNAphosphates through hydrogen bonds.

Protonation of lipids impacts the supramolecular and biological properties of their self-assembly.

We assessed in this work how a chemical structure difference could influence a supramolecular organization and then its biological properties. In our case study, we considered two amphiphilic lipidic gene vectors. The chemical difference was situated on their hydrophilic part which was either a pure neutral thiourea head or a mixture of three thiourea function derivatives, thiourea, iminothiol, and charged iminothiol.

Synthesis and functionalization of persistent luminescence nanoparticles with small molecules and evaluation of their targeting ability.

We have recently reported the design and use of inorganic nanoparticles with persistent luminescence properties. Such nanoparticles can be excited with a UV lamp for 2min and emit light in the near-infrared area for dozen of minutes without any further excitation. This property is of particular interest for small animal optical imaging, since it avoids the autofluorescence of endogenous fluorophores which is one major problem encountered when using fluorescent probes.

Altered HepG2 cell models using etomoxir versus tert-butylhydroperoxide.

Energetic failure which occurs in both ischemia/reperfusion and acute drug-induced hepatotoxicity is frequently associated with oxidative stress. This study displays the setting of a new cell culture model for hepatic energetic failure, i.e.

Controlling electron trap depth to enhance optical properties of persistent luminescence nanoparticles for in vivo imaging.

Focusing on the use of nanophosphors for in vivo imaging and diagnosis applications, we used thermally stimulated luminescence (TSL) measurements to study the influence of trivalent lanthanide Ln(3+) (Ln = Dy, Pr, Ce, Nd) electron traps on the optical properties of Mn(2+)-doped diopside-based persistent luminescence nanoparticles. This work reveals that Pr(3+) is the most suitable Ln(3+) electron trap in the diopside lattice, providing optimal trap depth for room temperature afterglow and resulting in the most intense luminescence decay curve after X-ray irradiation. This luminescence dependency toward the electron trap is maintained through additional doping with Eu(2+), allowing UV-light excitation, critical for bioimaging applications in living animals.

Development of a liposomal formulation of the natural flavonoid fisetin.

The natural flavonoid fisetin (3,3',4',7-tetrahydroxyflavone) has been shown to possess antiangiogenic and anticancer properties. Because of the limited water solubility of fisetin, our aim was to design and optimize a liposomal formulation that could facilitate its in vivo administration, taking into account the availability and cost of the various components. Several methods were evaluated such as probe sonication, homogeneization, film hydration and lipid cake formation.